In the Ricardo procedure and combustion chamber, high speed operation is effected using a divided chamber, with swirl organized circulation, the connection section between the pre-combustion chamber and the main chamber being constant during the whole cycle and of an optimized value of one percent of the active surface of the piston. On the other hand, the process and the combustion chamber have the disadvantage that during the fuel passage in both directions through the choke section high gasodynamic losses arise and cause relatively high specific fuel consumption and do not assure a complete organization of the fluid circulation in the divided chamber, the central and peripherical areas being left unorganized.
A unitary combustion chamber and its operating process are known in which the absence of chokes in the fuel path assures a relatively low fuel consumption, but this system has the disadvantage that high speed operation is not possible because of a reduced level of the swirl organization.